Re: [mpls] I-D Action: draft-andersson-mpls-open-dt-questions-00.txt

[Stewart Bryant <[e-mail]>]

Hi Loa

LDP really layers on an IGP in most practical networks and the IGP can flood this without missing a heartbeat.

- Stewart


> On 29 Apr 2021, at 14:41, Loa Andersson <[e-mail]> wrote:
> 
> Stewart,
> 
> I was that concerned about the amount of data that needs to be flooded, but rather that the mechanisms we have is insufficient.
> 
> In the LDP case an LSR informs its peers about capabilities, they are not flooded across the network
> 
> RFC 5561
> 
>   - Each LDP speaker is assumed to implement a set of enhancements,
>     each of which has an associated capability.  At any time, a speaker
>     may have none, one, or more of those enhancements "enabled".  When
>     an enhancement is enabled, the speaker advertises the associated
>     capability to its peers.  By advertising the capability to a peer,
>     the speaker asserts that it shall perform the protocol actions
>     specified for the associated enhancement.  For example, the actions
>     may require the LDP speaker to receive and process enhancement-
>     specific messages from its peer.  Unless the capability has been
>     advertised, the speaker will not perform protocol actions specified
>     for the corresponding enhancement.
> 
> An LSR that initiates an LSP with a maximum scanning depth depth need to know this for every LSR along the LSP.
> 
> /Loa
> 
> On 29/04/2021 12:25, Stewart Bryant wrote:
>> It is one additional capability field (no more than a byte) to flood and I find it hard to imagine that it would not scale.
> 
> -- 
> 
> Loa Andersson                        email: [e-mail]
> Senior MPLS Expert                          [e-mail]
> Bronze Dragon Consulting             phone: [phone]